I had a similar problem of feeling tired and weak most of the time, and I asked my physician what my problem was. She told me that according to my blood test result, I was lacking in Vitamin B12. But I was wondering what could a lack of vitamin B12 has to do with my level of energy. After all these years, I never took any vitamin daily and I had no intention of starting on any vitamins yet.
Just for the sake of maintaining the amount of B12 vitamin in my blood I started taking this vitamin B12 tablet. It comes in the form of tablet which dissolve when I put it in my mouth. I didn't even have to chew on the tablet. It taste great and doesn't taste yucky at all. I took the ones which had the power of 1200mcg. Since I was lacking by a great deal on Vitamin B12, that was why I started on the higher doses.
Right away, after taking the Vitamin B12 tablet, I began to feel more energetic and focus on doing things. My mind started to think clearer and better. I felt stronger and I didn't feel lazy even for a bit. So I tested myself by doing some gardening work of removing some unwanted weeds for one hour. After that, I still didn't lose much energy and I feel that I could go on for much longer than this. I realized that I could drive my car more focused and without falling sleepy on the wheels. In fact, throughout the day, my energy level was pretty much constant and I was feeling much happier too.
I went online and did a bit of research on benefits of Vitamin B12 and found a lot of positive thing about this Vitamin B12. It helps in proper breakdown of food and helps in better absorption of the broken down food. Without proper absorption of nutrients and minerals from our food, our body can't get much of the required nutrients and minerals. Even if we are to eat the proper food daily but our body can't absorb much of the nutrients, then our body gets weaker and weaker. Vitamin B12 also helps in the production of red blood cells which explains the reason why we feel more energetic, because there is an increase of red blood cells which helps to carry more oxygen in our blood.